A diversity of machinery including semiconductor manufacturing equipment, precision machines, measurement/inspection instruments, medical equipment, robots, assembling machines, micromachines and so on in recent years is designed compact or reduced in construction in favor of energy saving or high energy efficiency. Correspondingly, linear motion guide units for position control in reciprocation onboard the machinery stated just earlier are also needed compact or downsized in construction while expected to carry out highly precise position control, high speed and high response rate in operation, and further high reliability in dust-proofing and/or safety.
In a commonly-owned Japanese Laid-Open Patent Application No. 2007-300 759 there is disclosed a sliding device with onboard moving magnet linear motor, which is compact and simple in construction, better in high accuracy, high speed and high response rate in operation, high reliability in dust-proofing, and further easier in use and handling, and inexpensive in production.
The prior sliding device with onboard moving magnet linear motor recited earlier would be prove successful, to some extent, in high performance and ease in use and handling. Nevertheless, the advanced sliding devices with onboard moving magnet linear motor are more needed to meet anticipated design specifications of miniature or microscopic sliding device which is lower than ever in height a transverse section or in an overall height of the sliding device. This means that the smaller the sliding device in construction is, the less the propulsion of the sliding device. As a result, the sliding device is more prone to undergo any potentially adverse effects because of foreign matter such as dirt and dust caused by external atmosphere. To cope with this, the sliding device will be needed to have a dust-proof covering from an aspect of safety of the sliding device against the external environments.
Modern sliding devices with onboard moving magnet linear motor finding their applications in diverse fields including semiconductor manufacturing equipments, various assembling machines, measuring instrument, and so on are more needed to meet their downsizing or miniaturization and safety or protection against foreign material in addition to highly accurate position control, high speed and high response rate in operation. One of major challenges in the miniature sliding device, thus, resides in how to deal with the questions of protection against the external environments associated with downsizing or miniaturization in construction